In this chapter you will have learnt about the origins of toxicology in antiquity, mainly in relation to intentional poisoning. Some notable figures were mentioned especially Maimonides, Paracelsus, Orfila and Bernard. These individuals all helped toxicology develop from an art into a science. The breadth and scope of toxicology is illustrated by the variety of types of toxic substance to which we are exposed ranging from drugs, food additives, industrial chemicals, environmental pollutants, household poisons to natural toxins.